Green-blue dye and process of making same.



product.

UNITED STATE PATENT OFFICE.

' RENE BOHN OF MANNHEIM, GERMANY, ASSIGNOR TO THE BADISCHE ANILIN ANDSODAFABBIK, OF LUDWIGSHAFEN, GERMANY.

GREEN-BLUE DYE AND ROCESS OF MAKING SAME.

SPECIFICATION forming part of Letters Patent No. 633,950, datedseptember26, 1899. Application filed August 10, 1898. Serial No. 688,274. pe i enTo all whom it may concern:

Be it known that I, RENE BOHN, doctor of philosophy, a-citizen of theSwiss Republic, re-

siding at Mannheim, in the Grand Duchy of Baden andEmpire ofGermany,have invented new and useful Improvements in the Manufacture ofnew Coloring-Matter, of which the following is a specification.

As is'well known, naphthazarin can be prepared by heating1.5-dinitro-naphthalene with concentrated or fuming sulfuric acid, withor \vithout the addition of reducing agents. this mannfactu re a body isformed which is known as the naphthazarin intermediate The chemicalconstitution of this body has never been definitely ascertained anddescribed, and the substance is known under this name only, both inpatents and in general scientificliterature. his more particularlydescribed in the specification of the German Patent, No. 7 6,922,published on the 21st of August, 1894, in the following terms: Itssolution in concentrated sulfuric acid (containing about ninety-fivepercent. H 50 is brown. In dilute sulfuric acid it dissolves with a pureblue color. This color is not appreciably changed on adding caustic sodalye; but if an excess of hydrochloric acid be added to the dilutesulfuric-acid"solution the color turns to a greenish brown. thisnaphthazarin intermediate'product is a violet powder possessing ametallic luster, slightly soluble in water and giving a blue solution,which is not changed in color by the addition of sodium carbonate or ofa caustic soda lye. chloric acid it dissolves readily with a pure bluecolor. If the solution in dilute sulfuric acid be boiled, the blue colorchanges to red, and on cooling naphthazarin separates out. his thisnaphthazarin intermediate product which can be obtained, as described,from 1.5-dinitro-naphthalene, which constitutes the initial material formy invention. I

My present invention relates to the dis,- covery that on suitableoxidation of this in-- termediate product a new coloring-matter can beobtained which dyes on chrome-mordants, giving fast shades of a greenercast than those obtained with naphthazarin. I

The following example will serve to further illustrate the nature of theinvention. The parts are by weight:

\Vhen isolated,

In the presence of a little hydrothe addition of a suitable reducingagent.

Pour five hundred (500)- parts thereof, corresponding to about fifteen(15) parts of naphthazarin, into about two thousand five hundred (2,500)parts of water. A blue solution is obtained. parts of a solution ofsodium hypochlorite of 6 Baum. A green body separates out. Filter andwash free from acid. w

The invention is not restricted to the use of the materials orproportions given in the above example. For instance, instead of takingthe naphthazarin melt the isolated intermediate compound may be taken,say, in the form of its sodium salt, and instead of the hypochlorite asoxidizing agent other oxidiz ing agents may be used, such as potassiumbichromate. I

'The'new product can be used in dyeing either as such or in the form ofits bisulfite compound.

The new coloring-matter, in paste form, has a greenish-blue appearance.It gives a blue-violet solution in sodium-carbonate solution and a bluesolution in caustic soda lye.

It is but very little soluble in water, but on.

boiling gives a somewhat blue solution. Its solution in concentratedsulfuric acid is brown.

Now what I claim is- I 1. The new coloring-matter which can be obtainedby the oxidation of the naphthazarin intermediate product, ashereinbefore de+ fined, and which yields a blue solution in caustic sodalye and a brown solution in concentrated sulfuric acid and ablue-violet-sm lution with a solution of sodium carbonate;

witnesses.

RENE BOHN.

'WVitnesses:

GUSTAV L. LIETTENBERGER, AooLPn REUTLINGER.

Add to this two hundred (200)

